tide vs low water

tide and low water both are nouns.

Word	Noun	Adjective	Verb	Adverb
tide	Yes	No	Yes	No
low water	Yes	No	No	No

As nouns, low water is a hyponym of tide; that is, low water is a word with a more specific, narrower meaning than tide:

tide: the periodic rise and fall of the sea level under the gravitational pull of the moon
low water: the lowest (farthest) ebb of the tide

tide (noun)	low water (noun)
the periodic rise and fall of the sea level under the gravitational pull of the moon	the lowest (farthest) ebb of the tide
something that may increase or decrease (like the tides of the sea)
there are usually two high and two low tides each day